Polymerization of styrene-type compounds



' Patented Sept. 1943 POL 'rroNor srmNn-ma COMPOUNDS Hanna PeterStaudlnger, Ewell, England, asslgnor to The Distillers Company Limited,Edinburgh.

g ScotlanmaBritish compa y 4 'No' Drawing. Application'september 30,1940,Se- 1 M. 359,157. In Great Britain October 13,

e The present invention to the production tives with other polymerizableorganic compounds.

It is well known that the properties or polyq 4 claims (crest-st) 1.izable compounds are compounds which haveat or polymerized productstrom co-polymers oi: styrene and its nuclear alkyl substitutedderivaother polymerizable compounds and it has been proposed inter alia"to obtain a polymer either soluble in hydrocarbon solvents, or insolublein such solvents, by the polymerization oi styrene with dlvinylbenzene,and to obtain modified polymerization products by the co-polymerizationor aryl-substituted volefiries such as styrene with esters ofunsaturated acids such as crotonlc acid.

It has now been found that polymerized products of high molecular weightand having improved a physical and mechanical properties can be obtainedby effecting the partial polymerization oi the aryl-substitutednleflnesand then copolymerizing with other polymerizablecompounds.

According to the present invention polymerization products are obtainedfrom styrene-type compounds, by. adding the requisite amount or an ester01 crotonic acid having at least two double bonds in the moleculeseparated from one another by at least one atom or carbon to a mixtureof said monomeric styrene-type compounds and p lymers of the same andthereafter carrying the polymerization of the mixture to completion.

The method is particularly suitable for obtaining polymerizationproducts from styrene and esters or crotonicv acid such as vinylcrotonate and ethylene glycol dicrotonate. f

The method or carryins out theinvention con- I sists of initiatingpolymerization or the monomerio reactant, e. g., styrene, by any ci theusual methods or eiiecting polymerization-such as heat treatment, eitheralone or. in the presence of a polymerizing catalyst such as benzoylperoxide or radiation by ultra violet light, in the absence of any otherpolymerizable compound and carrying through the polymerization until asubstantial amount or polymer has been iormed. The initialpolymerization may be carried out to such an extent that from about 10to about 90%, preferably Irom about 40 to about 65% by weight, 01 themonomer is polymerized before the addition of the other polymerizablecompound is exfected. The other polymerizable compound is 'thenintroduced into, and thoroughly mixed with, the mixture of monomer andpolymer thus obtained, and polymerization is then carried least twodouble bonds in the molecule, separatedby at least one carbon-atom.Ethylene glycol dicrotonate and vinyl crotonatehave been found I to beparticularly suitable.- Compounds produced I by co-polymerization inaccordance with this process in addition 1; to having high molecularweights have the advantage or being thermoplastic. and are particularlysuitable for injection. moulding. The following are examples ofcarrylngouttheprocessofthisinvention. j

. s ani ze 1 100 c.c. of monomericstyrene of 97% purity (the remaining8% consisting of saturated hydrocarbons such as isopropyl benzene) wereheated in an atmosphere of nitrogen for 24 hours at 105." 0. until about70% byweisht of the monomer v the temperature to about 160 C. andremoving had been polymerized. 0.5 c.c. of vinyl crotonate was thenadded and polymerization was con-v tinued for 24 hours at 115 C. Afterraising non-polymerizable constituents by distillation underreducedpressure, 91 gms. of a transparent a resin were obtained, havinga molecular weight thermoplastic and was or 185,000; theresin wassoluble in benzene.

' l Example 2 v 50 gms. of polystyrene (80,000 molecular-j I weight),was dissolved in a mixture or 50 c.c. of monomeric styrene and 3 c.c. ofethylene glycol di-crotonate. The solution was then polymerized in anatmosphere of nitrogen for '22 hours at I 105 C. After removal of thenon-polymerlzable constituents by distillation under reduced pressure. aresin was obtained with a molecular weight of 144,000; the resin wassoluble in benzene. It was also thermoplastic and of a rubbery naturewhen hot.

Example 3 1.2 litres of monomeric styrene of %-purity (the remaining 15%consisting of inert saturated hydrocarbons) were heated in an oil-heatedvacuum-tight kneader for 18 hrs. at to 98 C., during which time 62% ofit had polymerized to a polymer of 104,000 molecular weight; 4 grams ofsorbitol hexacrotonate, dissolved in 40 cos. of monomeric styrene, werethen added to the mix and the whole was thoroughly kneaded and heatingwas continued at about C. for 40 hours.

Diluent and residual monomeric styrene were removed by vacuumdistillation by slowly raising the temperature to C. The resin wasrethrcush to completion. Suitable other polymers5 moved while still notand after cooling was broken zation product by subjecting an admixtureof styrene with polymers thereof to polymerizin conditions, in thepresence of an ester of crotonic acid having at least two double bondsin the molecule separated from one another by at least one carbon atom,until substantially complete polymerization i efiected.

2. The production of a styrene-type polymerization product by subjectingstyrene to polymerizing conditions whereby polymerization thereofensues, interrupting the polymerization prior to completion thereofwhereby an admixture of unpolymerized and polymerized styrene results,incorporating an ester of crotonic acid having at least two double bondsin the molecule separated from one another by at least one carbon atominto the product, and thereafter substantially completing thepolymerization of the admixture.

3. The process according to claim 1, wherein the admixture of styrenewith polymers thereof contains from about 10 to about 90 per cent byweight of styrene polymers.

4. The process according to claim 1, wherein the admixture of styrenewith polymers thereof contains from about 40 to about 65 per cent byweight of styrene polymers.

HANNS PETER STAUDINGER.

